Among vehicle body front structures, there are those having a structure in which a front bulkhead is provided to left and right front side frames and left and right upper members, and a cooling system component is provided to the front bulkhead.
The top part of the cooling system component is attached to an upper beam of the front bulkhead, and the bottom part of the cooling system component is attached to a lower beam of the front bulkhead via a lower support bracket.
The upper beam is fastened to left and right upper members by bolts so as to be capable of moving toward the rear of the vehicle body. The lower support bracket is fastened to the lower beam by bolts so as to be capable of moving toward the rear of the vehicle body.
According to the vehicle body front structure described above, when an impact load (input) acts on the front of the vehicle body due to a light collision, for example, the top part of the cooling system component moves with the upper beam toward the rear of the vehicle body. Similarly, the bottom part of the cooling system component moves with the lower support bracket toward the rear of the vehicle body. Vehicle body front structures are known in which damage to the cooling system component by the impact load is prevented due to the top and bottom parts of the cooling system component moving toward the rear of the vehicle body in this manner, such as the structure disclosed in Japanese Patent Application Laid-Open Publication No. 2009-137482 (JP-A 2009-137482), for example.
Usually in a vehicle body front structure, the upper beam and the lower beam are connected integrally by left and right side legs, thereby giving the front bulkhead a substantially triangular frame shape and ensuring rigidity in the front bulkhead.
However, in the vehicle body front structure disclosed in JP-A 2009-137482, since the upper beam is attached to left and right upper members so as to be capable of moving toward the rear of the vehicle body, steps must be taken to ensure the rigidity of the front bulkhead, in which there is room for improvement.
Furthermore, in the vehicle body front structure disclosed in JP-A 2009-137482, the upper beam is fastened to the left and right upper members by bolts so as to be capable of moving toward the rear of the vehicle body, and the lower support bracket is fastened to the lower beam by bolts so as to be capable of moving toward the rear of the vehicle body. Therefore, when the upper beam is assembled on the upper members (the vehicle body), the fastening load of the bolts must be adjusted so that the upper beam is capable of moving toward the rear of the vehicle body. Similarly, when the lower support bracket is assembled on the lower beam (the vehicle body), the fastening load of the bolts must be adjusted so that the lower support bracket is capable of moving toward the rear of the vehicle body.
Thus, when the upper beam and the lower support bracket are assembled as component units, adjusting the fastening load requires more labor than adjusting the fastening loads of bolts. Therefore, labor is required for assembling the cooling system component on the front bulkhead, which also leaves room for improvement.
Furthermore, the vehicle body front structure disclosed in Japanese Laid-open Patent Publication No. 2009-137482 has the lower support bracket located between the lower beam and the bottom part of the cooling system component in order to allow the bottom part of the cooling system component to move toward the rear of the vehicle body. Consequently, a space must be ensured for placing the lower support bracket between the lower beam and the bottom part of the cooling system component.
However, when a space is ensured between the lower beam and the bottom part of the cooling system component, some of the air led in from the front of the vehicle body while the vehicle is traveling flows toward the rear of the vehicle body (the engine compartment) via this space. Therefore, it is difficult for air led in from the front of the vehicle to be led efficiently to the cooling system component, which also leaves room for improvement.